Method for inhibiting disease associated with the human immunodeficiency virus through the use of monoclonal antibodies directed against anti-self cytotoxic T-lymphocytes or their lytics

ABSTRACT

Methods for treating and inhibiting disease and symptoms associated with the human immunodeficiency virus (HIV) are provided. The method includes transforming the human immunodeficiency virus (HIV) infection into a nonserious disease through the infusion of monoclonal antibodies directed against particular antigens on anti-self, anti-CD4 cytotoxic T-lymphocytes.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of application U.S. Ser. No.08/302,113, filed Sep. 7, 1994, now U.S. Pat. No. 5,424,066 which is afile wrapper continuation of U.S. Ser. No. 08/165,751, filed Dec. 13,1993, now abandoned, which application is a continuation-in-partapplication of prior application U.S. Ser. No. 08/033,405, filed Mar.19, 1993, now abandoned.

TECHNICAL FIELD

The present invention relates generally to methods for treating humandisease conditions associated with the human immunodeficiency virus(HIV) and more particularly to the use of monoclonal antibodies directedagainst anti-self cytotoxic T-lymphocytes or their lytics in order toinhibit or treat HIV and related HIV diseases.

BACKGROUND OF THE INVENTION

Several viruses produce latent infection in humans and can reactivate toproduce recrudescent or persistent disease. One such disease is thehuman immunodeficiency virus (HIV). HIV is associated with a progressivecatastrophic disease in certain primates, including humans. Humansinfected with HIV experience proliferation of a certain class of whiteblood cells known as cytotoxic T-lymphocytes (CTL). The final stage ofthis disease is commonly known as acquired immune deficiency syndrome(AIDS).

It is well known in the art that the clinical signs and symptoms of AIDSare primarily due to a profound loss of all lymphocytes marked with theCD3 and CD4 antigens (CD4+ T-lymphocytes). It is also generally acceptedthat the infectious agent in AIDS is the human immunodeficiency virus(HIV). Although HIV infects and destroys CD4+ cells, the number of cellsinfected is inadequate to account for the profound and indiscriminateloss of these cells that occurs in individuals infected with HIV. It hasbeen suggested by those in the field that autoimmunity may play a rolein the pathogenesis of AIDS. However, few have suspected a pathogeniccytotoxic T-lymphocyte (CTL).

Rather, it is generally accepted by those skilled in the art that CTL'sare beneficial for those infected with HIV since it is believed CTL'shelp control the infection, i.e., CTL's are believed to beprognosticators that delay the progression of AIDS. Kilmas, et at,"Phase I Trial of Adoptive Therapy with Purified CD8 Cells in HIVInfection", Int. Conf. AIDS, Jul. 19-24, 1992; Abstract No. POB 3446,for example, have described infusion of CTL's into the bloodstream ofHIV-infected patients as an experimental method of treatment. Thisparticular type of infusion was directed to the mitogen-expandedcolonies of the host patient's autologous CD8+ cells, a lymphocytepopulation that includes CTL's.

However, Zarling, et at, "HIV-Infected Humans, But Not Chimpanzees, HaveCirculating Cytotoxic T-Lymphocytes That Lyse Uninfected CD4+ Cells", J.Immunol., 1990; 144: 2992-98 have shown that HIV-infected humans have ananti-self, anti-CD4 CTL in their circulating blood that lyses healthy,uninfected CD4+ cells. No such CTL was found in the blood ofHIV-seronegative humans. Moreover, no such CTL or suicide cell was foundin the blood of HIV-infected chimpanzees. This is significant becauseHIV infection manifests as a nonpathogenic colonization in the blood andtissue of chimpanzees.

BRIEF SUMMARY OF THE INVENTION

HIV vaccine studies have shown that reducing CTL's causes the host's CD4count to go up. The present invention is based on the deduction that thereason CD4 counts go down in the first place as a result of HIVinfection is because among the various types of CTL's, there must be ananti-self, anti-CD4 CTL. Thus, the maladaptive CTL synthesized by humansis the factor that transforms HIV infection into a catastrophic disease.This is confirmed by the work of Zarling et al, who found that becauseHIV infection does not lead to any serious disease in chimpanzees, it isthe anti-self, anti-CD4 suicide cell, rather than HIV itself, that isdirectly responsible for the disease associated with HIV infection inhumans.

The destructive role of the anti-self, anti-CD4 cytotoxic T-lymphocyteis overcome according to the teachings of the present invention throughthe use of monoclonal antibodies directed against one or more particularantigens on the anti-self, anti-CD4 killer cell or antigens on thelytics produced by such killer cell. Through infusion of particularmonoclonal antibodies directed against such antigens, the anti-self,anti-CD4 cytotoxic T-lymphocytes or their lytics as the case may be areneutralized to prevent an HIV positive patient from developing AIDS orto cure the disease itself if the disease has sufficiently advanced intoAIDS. In addition, use of adhesion antibodies neutralizes cellsproducing HIV to improve the health of infected patients.

It is thus a primary objective of the present invention to provide amethod for preventing and/or curing HIV disease by eliminating orneutralizing anti-self, anti-CD4 CTL's or their lytics from thecirculating blood of an HIV-infected patient through the infusion ofmonoclonal antibodies directed against the antigens presented by suchcells or their lytics.

These and other objects of the invention are provided in a method whichtransforms HIV into a nonserious infection. This is accomplished byneutralizing or removing the anti-self, anti-CD4 suicide cell from thecirculating blood of an individual infected with HIV or who is at riskof such infection, and by neutralizing or removing HIV-producing cells.

The foregoing has outlined some of the more pertinent objects of thepresent invention. These objects should be construed to be merelyillustrative of some of the more prominent features and applications ofthe invention. Many other beneficial results can be attained by applyingthe disclosed invention in a different manner or modifying the inventionas will be described. Accordingly, other objects and a fullerunderstanding of the invention may be had by referring to the followingDetailed Description of the preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and theadvantages thereof, reference should be made to the following DetailedDescription taken in connection with the accompanying drawings in which:

FIG. 1 is a schematic representation of AIDS pathogenesis showing therole of the anti-self, anti-CD4 CTL in the progression of HIV diseaseinto AIDS;

FIG. 2 is a schematic representation of a S6F1 monoclonal antibodyattached to the S6F1 antigen on the anti-self CTL according to theteachings of the present invention.;

DETAILED DESCRIPTION

By way of brief background, it is well known that cytotoxicT-lymphocytes ("CTL's") are white blood cells that kill other cells. Ifa CTL kills foreign cells (such as bacteria, fungus, viruses, cancer orthe like), it is deemed a normal cytotoxic T-lymphocyte. On the otherhand, if the CTL kills healthy cells of the body that the cell belongsto, it is deemed an "anti-self" cytotoxic T-lymphocyte. In either case,such cells typically function by destroying the cell membrane of thetarget cell using one or more "lytics", which are known chemicalcompounds. The process of breaking apart the target cell is referred toas lysis.

CTL's belong to a group of lymphocytes that carry a CD8 antigen. HIVvaccine studies have shown that reducing CTL's causes a host patient'sCD4 count to go up. From this evidence, it has now been recognized thatthe reason CD4 counts go down in the first place as a result of HIVinfection is because among the CTL's, there must be an anti-self,anti-CD4 CTL. Thus, AIDS is caused not by the infection itself, but by awhite blood cell made in response to the infection.

FIG. 1 is a schematic representation of what is believed to be the AIDSpathogenesis. As seen in this figure, the HIV infection leads to thedestruction of CD4 cells through infection and budding of new HIVvirions. This process generates an immunologic signal that causes theproliferation of anti-self, anti-CD4 cytotoxic T-lymphocytes. As shownin FIG. 1, these cells carry various known antigens including, withoutlimitation, DR, CD8, LFA-1, ICAM and TCR-1. The cells also include oneor more lytics which are chemical compounds used to attack the targetcell; such lytics also include antigens. The anti-self, anti-CD4 CTL'sor their lytics then destroy healthy activated CD4 cells. Thus AIDS isprobably caused not by the infection itself but by the white blood cellsmade in response to the infection.

The present invention overcomes the destructive action of the anti-self,anti-CD4 CTL's or their lytics by infusion of monoclonal antibodies intothe bloodstream of the host patient. It also overcomes the deleteriouseffects of HIV replication. As is known in the art, a monoclonalantibody is an antibody that is made from one cell so that all resultingantibodies are the same. The standard process of making monoclonalantibodies is described in, for example, Immunology III, by Joseph A.Bellanti (W. B. Sanders, 1985) at pages 99-100, which teachings areincorporated herein by reference. Of course, the particular method formaking the monoclonal antibodies is not limited to such technique and itis envisioned that any technique for making such antibodies is withinthe practice of the invention. The antibodies are designed to bedirected toward a particular antigen on the anti-self, anti-CD4 CTL oran antigen on lytics produced by such CTL.

Referring now to FIG. 2, a representation is shown of the particulartreatment method. As seen, monoclonal antibodies directed against aspecific antigen, in this case the S6F1 antigen on the anti-self,anti-CD4 CTL, are produced in the conventional manner and infused intothe bloodstream of the host patient. The particular monoclonal antibodyis shown attached to the antigen. Such mating flags the immune systemand triggers a known immunological response to cause the body to attemptto neutralize the cells. In this manner, the anti-self, anti-CD4 CTLcell is neutralized. A similar mechanism would be used if the particularmonoclonal antibodies were directed to an antigen on a lyric produced bythe CTL cell.

According to the invention, monoclonal antibodies are directed to one ormore of the antigens on the CTL cell or its lytics. Under somecircumstances, it may be desirable to limit the type of monoclonalantibodies to certain specific antigens. Or, it may be desirable totreat the patient first with a particular monoclonal antibody and thenuse another monoclonal antibody later, or to use multiple antibodiessimultaneously. Thus, for example, since many cells (besides the CTL)carry the CD8 antigen, it may be desirable to limit use of the CD8monoclonal antibodies until an initial improvement in the patient'simmune system is established through some other antigen target. Thepresent invention is intended to cover all such variations on thesequence and scope of how the particular monoclonal antibodies areinfused.

Although not meant to be limiting, the monoclonal antibodies arepreferably infused once per month over a period of between 10 minutes inaccordance with one embodiment of the invention. The mount of antibodiesshould typically be about 0.1 milligrams per kilogram of the patient'sbody weight. The daily regimen is preferably repeated as needed tomaintain an effective immune response. As used herein, an effectiveimmune response will typically mean that the patient's CD4/CD8 ratio isreturning to normal, accepted levels. While different laboratories havedifferent norms, usually this will mean a ratio of about 1:1.Thereafter, maintenance treatments may be required depending on thecourse of the infection or disease. Preferably, the patient's bloodshould be measured on a monthly basis to track the progress of thetreatment. Although not meant to be limiting, the monoclonal antibodiesare typically supported in a suitable carrier such as PBS Ringer'slactate solution or normal saline. The infusion may be effected using aconventional syringe and line or infusion pump of known manufacture.

As discussed above, the present invention thus exploits the belief thatit is the immunogenic component of the HIV infection that results in theprogression of HIV to a fatal disease. The significance of the presentinvention is that it provides a method of neutralizing the maladaptiveCTL (or its lytics) that transform HIV infection into AIDS. Thusaccording to the invention the HIV disease can be transformed from anon-serious infection, and HIV infection can be prevented from becominga serious disease, if the suicide cell and/or its lytics are neutralizedin, or removed from, an individual infected with HIV or at risk of suchinfection.

Thus the method transforms HIV infection through the infusion ofmonoclonal antibodies directed against anti-self CTL's or their lytics.This approach recognizes that monoclonal antibodies have a direct andspecific effect against the body of specific antigens. According to theinvention, a necessary but sufficient dose of monoclonal antibodies isinfused into the bloodstream until anti-self CTL's have been eliminatedor neutralized and HIV disease cured, or anti-self CTL's are incapableof proliferating and HIV disease has thereby been prevented.

EXPERIMENTAL

A patient, infected with the HIV virus for about ten years, had beenreceiving treatment by injection of his own T cells to achieve abiphasic elevation of the CD4/CD8 ratio. The patient had been respondingto such injections for a period of about fifteen months of treatment. Atthat time, the patient had also been on ddI for approximately two years.However, given the advanced stage of the patients' disease, both ofthese treatments were no longer providing beneficial results. In fact,HIV could be cultured from his blood cells even when the blood wasdiluted out to about one part per 3,120. Even at such dilution, the p24antigenemia, which is a measure of HIV activity, was quite high at about300 pg/ml.

The patient was then treated in accordance with the method of thepresent invention. In particular, the patient was given about 68 mg ofS6F1 antibodies over a period of 14 days. The 68 mg corresponded to 1mg/kg of the patient's body weight. A few days after completing thetreatment, the AIDS virus could no longer be cultured from thecirculating blood cells of the patient. Thus, treatment in accordancewith the present invention reduces viral load in the circulating bloodof patients with long-term HIV infection.

The speed with which infectious cells disappeared from the patient'scirculating blood suggests that some phagocyte may have destroyed theinfected cells. In fact, the patient experienced a marked increase inmonocytes during treatment, and the treating physician believed at thetime, that these monocytes could be destroying the infected cells.However, the antiviral effect could also be due to the blockage of theadhesion pathway needed for communication between antigen presentingcells, thus rendering HIV-infected cells noninfectious.

Depending on the progression of disease in the individual and otherfactors, the dosage range varies from about 0.01 to about 1.0 mg/kg bodyweight for a patient treated in accordance with the present invention.

The effectiveness of Applicant's method using LFA-1, ICAM-1, ICAM-2 ANDICAM-3 monoclonal antibodies on CD4+ T lymphocyte depletion isillustrated in Butini, et al, "Intercellular adhesion molecules(ICAM)-1, ICAM-2 and ICAM-3 function as counter-receptors for lymphocytefunction-associated molecule 1 in human immunodeficiency virus-mediatedsyncytia formation", European Journal of Immunology, 1994, Vol. 24, pp.2191-2195. The monoclonal antibodies utilized within the experiementsdiscussed in the Butini article included the hybridoma cell lines forTS1/22 and TS1/18 monoclonal antibodies, directed against LFA-1antigens. RR1/1, CBR-IC2/1 and CBR-IC2/2 monoclonal antibodies weredirected against ICAM-1 and ICAM-2 antigens. CBR-IC3/1 and CBR-IC3/2monoclonal antibodies were directed against two different isotopes ofICAM-3 antigens.

Particularly with respect to CD4+ T lymphocyte depletion, the treatmentof cultures with LFA-1 monoclonal antibodies significantly reduced theamount of CD4+ T cell depletion in the treated cultures as compared withthe untreated cultures. The CD4+ T cells remain completely viable untilday ten after infection and showed only a minor depletion of CD4+ Tcells (approximately 20%) at day 19. In untreated cultures, a decreasein CD4+ T cell viability was evident at day 10, and by day 16 thedepletion of CD4+ T cells was 80%. Similar results were obtained incultures treated with ICAM-1, ICAM-2, and ICAM-3 monoclonal antibodies.However, the depletion protection of day 19 was not as high as thatachieved with LFA-1 monoclonal antibodies and the depletion was in the50% range.

An alternative embodiment of the present invention also serves as apreventative measure for health care workers. In particular, anHIV-infected individual requiring invasive medical or dental procedures,undergoes treatment in accordance with the present invention prior tosuch surgery or procedures. In this manner, infectious cells in thecirculating blood of the HIV-infected individual are reduced, therebyprotecting health care workers involved with the surgical procedures byreducing the possibility of HIV exposure.

It should be appreciated by those skilled in the art that the specificembodiments disclosed above may be readily utilized as a basis formodifying or designing other techniques or processes for carrying outthe same purposes of the present invention. Thus, for example, otherdelivery vehicles or techniques may be used for delivering themonoclonal antibodies to the bloodstream. It should also be realized bythose skilled in the art that such equivalent processes do not departfrom the spirit and scope of the invention as set forth in the appendedclaims.

What is claimed is:
 1. A method for treating a patient having suppressedimmune function resulting from human immunodeficiency virus infection inorder to elevate the number of CD4+ cells in said patient, comprisingthe steps of:(a) infusing a dose of a monoclonal antibody selected fromthe group consisting of antibodies which specifically bind to ICAM-1,ICAM-2, and ICAM-3, said dose being between about 0.1-1.0 milligrams ofsaid monoclonal antibody per kilogram of the patient's weight; and (b)repeating said infusion as necessary.